USB extension socket with efficient rectification output

Abstract

The utility model provides a USB extension socket with efficient rectification output, which relates to the technical field of USB and comprises an alternating current circuit, a bridge rectifier circuit, a filter circuit, a step-down circuit and a USB output circuit. The input end of the alternating-current circuit is electrically connected with a live wire and a zero wire, the output end of the alternating-current circuit is electrically connected with the USB output circuit after being sequentially connected in series with the bridge rectifier circuit, the filter circuit and the step-down circuit, the USB output circuit comprises a current-limiting protection chip, a Type-C interface and a Type-A interface, the Type-C interface and the Type-A interface are both electrically connected with the current-limiting protection chip, and the Type-A interface is electrically connected with the current-limiting protection chip. The grounding ends of the Type-C interface and the Type-A interface are grounded through a current detection resistor, and the two ends of the current detection resistor are electrically connected with the current limiting protection chip. Whether current output exceeds the standard or not is judged by detecting voltage values at the two ends of the current detection resistor, output is cut off through the current limiting protection chip under the condition of large current, and stable output power is guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of USB power strips, and in particular to a USB power strip with high-efficiency rectifier output. Background Art

[0002] With the widespread adoption of electronic devices, USB power strips have become an indispensable power supply in our daily lives and work. With the continuous advancement of technology and increasing demand for electronic device charging performance, USB power strips with efficient rectifier outputs have become an urgent market need. However, traditional USB power strips often suffer from inefficient rectifier outputs.

[0003] In early USB power strip designs, the rectification circuit typically used simple diodes. While this method can convert AC power to DC, the large forward voltage drop of the diodes results in energy loss, reducing the overall rectification efficiency of the power strip. This not only wastes energy but can also generate significant heat during high-power output, impacting the power strip's stability and lifespan.

[0004] Furthermore, the output voltage and current stability of traditional USB power strips are less than ideal. When multiple devices are connected and charging simultaneously, voltage fluctuations and uneven current distribution are prone to occur, which can damage connected electronic devices and reduce charging speed and efficiency. Utility Model Content

[0005] The technical problem to be solved by the present invention is the problem of low output efficiency and unstable power of USB power strips in the prior art. In order to overcome the above defects of the prior art, the present invention provides a USB power strip with high-efficiency rectifier output.

[0006] The utility model provides a USB power strip with high-efficiency rectifier output, comprising an AC circuit, a bridge rectifier circuit, a filter circuit, a step-down circuit and a USB output circuit;

[0007] The input end of the AC circuit is electrically connected to the live wire and the neutral wire. The output end of the AC circuit is electrically connected to the USB output circuit after being connected in series with a bridge rectifier circuit, a filter circuit, and a step-down circuit. The USB output circuit includes a current limiting protection chip U4, a Type-C interface, and a Type-A interface. The Type-C interface and the Type-A interface are both electrically connected to the current limiting protection chip U4. The ground ends of the Type-C interface and the Type-A interface are both grounded through a current detection resistor, and both ends of the two current detection resistors are electrically connected to the current limiting protection chip U4.

[0008] Compared with the existing technology, the present application discloses a USB power strip with high-efficiency rectifier output, which has the following advantages: the ground terminals of the Type-C interface and the Type-A interface are both grounded through a current detection resistor. By detecting the voltage value across the current detection resistor, it is determined whether the current output exceeds the standard. In the event of high current, the output is promptly cut off through the current limiting protection chip U4, ensuring the stability of the output power and preventing high-power output from damaging the load.

[0009] In one possible embodiment, a PD fast charging feedback circuit is further included, and the PD fast charging feedback circuit includes a photocoupler U3; the positive output end of the step-down circuit is electrically connected in series with a capacitor C6 and the positive electrode of the photocoupler U3, and a resistor R12 is connected in parallel at both ends of the capacitor C6. The negative electrode of the photocoupler U3 is electrically connected to the current limiting protection chip U4, and the positive electrode of the photocoupler U3 is electrically connected to the negative electrode of the photocoupler U3 through the resistor R1. The emitter of the photocoupler U3 is grounded, and the collector of the photocoupler U3 is electrically connected to the voltage feedback end of the step-down circuit. The collector of the photocoupler U3 is grounded through the series resistor R10 and the capacitor C4.

[0010] Compared with the existing technology, by setting the optocoupler U3, timely feedback can be achieved when a large voltage is output, and the current limiting protection chip U4 can also cut off the output in time to ensure the stability of the output power and prevent high power output from damaging the load.

[0011] In one possible embodiment, the AC circuit includes a power plug, a fuse F1, a thermistor RT1, and an electromagnetic interference filter; the power plug is provided with a live wire connection end for electrically connecting to the live wire and a neutral wire connection end for electrically connecting to the neutral wire, the live wire connection end is electrically connected to the first AC input end of the bridge rectifier circuit through the series fuse F1, and the neutral wire connection end is electrically connected to the second AC input end of the bridge rectifier circuit through the thermistor RT1; the electromagnetic interference filter includes a capacitor CX1, a resistor RX1, a resistor RX2, a resistor RX3, and a resistor RX4; the capacitor CX1 is electrically connected between the first AC input end and the second AC input end of the bridge rectifier circuit, the resistors RX1 and RX2 are connected in series and then connected in parallel to both ends of the capacitor CX1, and the resistors RX3 and RX4 are connected in series and then connected in parallel to both ends of the capacitor CX1.

[0012] Compared with existing technologies, electromagnetic interference filters are used to resist surge current and voltage in the live and neutral wires, protecting equipment from instantaneous high voltage impacts; thermistors are used to detect internal temperature, and the device automatically stops working when the temperature is too high.

[0013] In one possible embodiment, the filter circuit includes an inductor L1, an inductor RL2, an electrolytic capacitor EC1, an electrolytic capacitor EC2, a capacitor C1, a capacitor C2, a diode D1, a resistor R1, a resistor R6 and a resistor R7; the DC positive electrode of the bridge rectifier circuit is electrically connected to the positive input terminal of the step-down circuit through the inductor L1, the DC negative electrode of the bridge rectifier circuit is grounded through the inductor RL2, and the electrolytic capacitor EC1 is electrically connected to the DC positive electrode of the bridge rectifier circuit and the DC negative electrode of the bridge rectifier circuit. Between the DC negative pole, the electrolytic capacitor EC2 is electrically connected between the positive input terminal and the negative pole of the step-down circuit; the positive input terminal of the step-down circuit is connected in series with the capacitor C1, the capacitor C2 and the resistor R6, and then electrically connected to the negative input terminal of the step-down circuit, the resistor R1 is connected in parallel to both ends of the capacitor C1, the resistor R7 is connected in parallel to both ends of the resistor R6, the connection end of the capacitor C1 and the capacitor C2 is electrically connected to the negative pole of the diode D1, and the connection end of the capacitor C2 and the resistor R6 is electrically connected to the positive pole of the diode D1.

[0014] Compared with the existing technology, the DC voltage output from the rectifier output end is smoothed by the filter circuit to ensure signal stability, and the capacitor is connected in parallel at both ends of the electrolytic capacitor to further filter out high-frequency ripple.

[0015] In one possible embodiment, the step-down circuit includes a transformer L2 and a step-down chip U1; the primary positive pole of the transformer L2 is the positive input terminal of the step-down circuit, and the primary negative pole of the transformer L2 is the negative input terminal of the step-down circuit. The primary positive pole of the transformer L2 is connected in series with resistors R4 and R5 and then electrically connected to the power supply terminal of the step-down chip U1, and the primary negative pole of the transformer L2 is electrically connected to the output current terminal of the step-down chip U1; the power supply terminal of the step-down chip U1 is grounded through electrolytic capacitor EC3 and capacitor C5, respectively, and the current feedback terminal cs of the step-down chip U1 is grounded through resistors RS1 and RS2, respectively.

[0016] Compared with the existing technology, the filtered DC voltage is reduced to the required voltage through the voltage drop chip U1 and the transformer L2, which is easy to control.

[0017] In a possible implementation, the buck chip U1 is an OB2734 buck chip.

[0018] In one possible embodiment, the step-down circuit is electrically connected to the USB output circuit through a synchronous rectifier circuit; the synchronous rectifier circuit includes a synchronous rectifier chip U2, a resistor R13, a capacitor C7 and a capacitor C8; the transistor output pins of the synchronous rectifier chip U2 are all electrically connected to the negative output end of the step-down circuit, the negative output end of the step-down circuit is connected in series with the resistor R13 and the capacitor C7 and is electrically connected to the negative input end of the USB output circuit, the ground end of the synchronous rectifier chip U2 is electrically connected to the negative input end of the USB output circuit, and the power supply end of the synchronous rectifier chip U2 is grounded through the capacitor C8.

[0019] Compared with the prior art, efficient rectification is achieved through the connection setting of the synchronous rectification chip U2.

[0020] In a possible implementation, the synchronous rectification chip U2 is an OB2013 synchronous rectification chip.

[0021] In a possible implementation, the current limiting protection chip U4 is a HUSB382 current limiting protection chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a system block diagram of a USB power strip with high-efficiency rectifier output in the utility model;

[0023] Figure 2 This is a circuit diagram of the AC circuit, bridge rectifier circuit, filter circuit, and step-down circuit of a USB power strip with high-efficiency rectifier output in the utility model;

[0024] Figure 3 The utility model is a circuit diagram of a USB output circuit of a USB power strip with high-efficiency rectifier output. DETAILED DESCRIPTION

[0025] First, those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the embodiments of the present application and are not intended to limit the scope of protection of the embodiments of the present application. Those skilled in the art may adjust them as needed to suit specific application scenarios.

[0026] In the description of the embodiments of this application, it should be noted that, unless otherwise specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of this application based on the specific circumstances.

[0027] The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] See also Figures 1 to 3 As shown, an embodiment of the present application discloses a USB power strip with high-efficiency rectification output, including an AC circuit, a bridge rectifier circuit, a filter circuit, a step-down circuit and a USB output circuit.

[0029] The input end of the AC circuit is electrically connected to the live wire and the neutral wire. The output end of the AC circuit is connected in series with a bridge rectifier circuit, a filter circuit, and a step-down circuit, and then electrically connected to the USB output circuit. The USB output circuit includes a current limiting protection chip U4, a Type-C interface, and a Type-A interface. The Type-C interface and the Type-A interface are both electrically connected to the current limiting protection chip U4. The ground terminals of the Type-C interface and the Type-A interface are both grounded through a current detection resistor, and both ends of the two current detection resistors are electrically connected to the current limiting protection chip U4.

[0030] The current limiting protection chip U4 controls whether the Type-C interface and Type-A interface cut off the output according to the voltage value across the two current detection resistors.

[0031] The ground terminals of both the Type-C and Type-A interfaces are connected to the ground through a current detection resistor. By detecting the voltage across the current detection resistor, it is determined whether the current output exceeds the standard. In the event of high current, the current limiting protection chip U4 is used to cut off the output in time to ensure the stability of the output power and prevent high power output from damaging the load.

[0032] The current limiting protection chip U4 also integrates an intelligent charging management chip that can automatically identify the type of connected device and dynamically adjust the output current and voltage based on the device's needs, achieving fast, safe, and efficient charging. Specifically, the current limiting protection chip U4 is the HUSB382 current limiting protection chip.

[0033] The Type-C interface and Type-A interface are used to connect devices to be charged, and multiple Type-C interfaces and Type-A interfaces can be set.

[0034] Among them, in this embodiment, the bridge rectifier circuit is a general circuit and will not be described in detail here. The bridge rectifier circuit can efficiently convert the input AC power into DC power. The high-performance diodes selected have low conduction voltage drop and fast recovery characteristics, which greatly reduces the energy loss in the rectification process.

[0035] In this embodiment, a PD fast charging feedback circuit is also included, and the PD fast charging feedback circuit includes a photocoupler U3.

[0036] The positive output end of the step-down circuit is electrically connected in series with a capacitor C6 and the positive electrode of the photocoupler U3. A resistor R12 is connected in parallel at both ends of the capacitor C6. The negative electrode of the photocoupler U3 is electrically connected to the current limiting protection chip U4. The positive electrode of the photocoupler U3 is electrically connected to the negative electrode of the photocoupler U3 through the resistor R1. The emitter of the photocoupler U3 is grounded. The collector of the photocoupler U3 is electrically connected to the voltage feedback end of the step-down circuit. The collector of the photocoupler U3 is grounded through the series resistor R10 and the capacitor C4.

[0037] The HUSB382 current-limiting protection chip communicates with external devices through a pre-set OPTO channel to determine the required output voltage and current specifications. Optocouplers, as isolation devices, are used to transmit signals between circuits at different potentials. Once the protocol chip determines the output setpoint, it controls the current flowing through the optocoupler's internal LED to adjust the light intensity. The FB pin of the OB2734 buck chip receives current from the optocoupler's phototransistor. Based on the received current, the FB pin adjusts the internal control mechanism, thereby varying the buck chip's duty cycle to regulate the output voltage. The coordinated operation of the current-limiting protection chip, optocoupler, and buck chip's FB pin enables precise and dynamic voltage regulation to meet the charging needs of different devices.

[0038] The power strip also features internal overvoltage, overcurrent, and short-circuit protection circuits. If the output voltage is too high, the current is too high, or a short circuit is detected, the protection circuits will quickly cut off the output, protecting both the connected devices and the power strip itself. This USB power strip features a highly efficient rectifier output. By optimizing the design of the rectifier, filter, and control circuits, this significantly improves the output efficiency, providing stable, fast, and safe charging for a variety of electronic devices.

[0039] Specifically:

[0040] Overvoltage protection: Use a voltage detection chip to monitor the output voltage. When the output voltage exceeds the set value, the control circuit cuts off the output to protect the connected equipment.

[0041] Overcurrent protection: A current detection resistor is set in each USB output circuit. When the output current exceeds the set value, the control circuit limits the output current or cuts off the output.

[0042] Intelligent identification: Using intelligent identification chip, it can automatically detect the type of connected USB device (such as mobile phone, tablet, power bank, etc.) and provide the corresponding optimal charging current to achieve fast charging.

[0043] Among them, the AC circuit is used to connect the external AC power supply and perform preliminary filtering and protection on the input AC power, including the power plug, fuse F1, thermistor RT1, and electromagnetic interference filter.

[0044] The power plug is provided with a live wire connection terminal for electrically connecting to the live wire and a neutral wire connection terminal for electrically connecting to the neutral wire. The live wire connection terminal is electrically connected to the first AC input terminal of the bridge rectifier circuit via a series fuse F1, and the neutral wire connection terminal is electrically connected to the second AC input terminal of the bridge rectifier circuit via a thermistor RT1.

[0045] The electromagnetic interference filter includes a capacitor CX1, a resistor RX1, a resistor RX2, a resistor RX3, and a resistor RX4; the capacitor CX1 is electrically connected between the first AC input terminal and the second AC input terminal of the bridge rectifier circuit, the resistors RX1 and RX2 are connected in series and then connected in parallel across the capacitor CX1, and the resistors RX3 and RX4 are connected in series and then connected in parallel across the capacitor CX1.

[0046] Electromagnetic interference filters are used to resist surge current and voltage in the live and neutral lines, protecting the equipment from instantaneous high voltage impacts; thermistors are used to detect internal temperature, and the system automatically stops working when the temperature is too high.

[0047] The power plug is used to connect to an external AC power source, that is, directly plugged into a socket. Further, a power indicator light and a main switch button can also be provided.

[0048] The filter circuit includes an inductor L1, an inductor RL2, an electrolytic capacitor EC1, an electrolytic capacitor EC2, a capacitor C1, a capacitor C2, a diode D1, a resistor R1, a resistor R6 and a resistor R7;

[0049] The DC positive electrode of the bridge rectifier circuit is electrically connected to the positive input terminal of the step-down circuit through the inductor L1, the DC negative electrode of the bridge rectifier circuit is grounded through the inductor RL2, the electrolytic capacitor EC1 is electrically connected between the DC positive electrode of the bridge rectifier circuit and the DC negative electrode of the bridge rectifier circuit, and the electrolytic capacitor EC2 is electrically connected between the positive input terminal and the negative electrode of the step-down circuit;

[0050] The positive input terminal of the step-down circuit is electrically connected to the negative input terminal of the step-down circuit after being connected in series with capacitor C1, capacitor C2 and resistor R6. Resistor R1 is connected in parallel across capacitor C1, and resistor R7 is connected in parallel across resistor R6. The connection end of capacitor C1 and capacitor C2 is electrically connected to the negative electrode of diode D1, and the connection end of capacitor C2 and resistor R6 is electrically connected to the positive electrode of diode D1.

[0051] The filter circuit is composed of large-capacity electrolytic capacitors and inductors, which effectively smooths the rectified DC power, reduces voltage fluctuations, and provides stable power for USB output.

[0052] Among them, the step-down circuit includes a transformer L2 and a step-down chip U1;

[0053] The primary positive electrode of the transformer L2 is the positive input terminal of the step-down circuit, and the primary negative electrode of the transformer L2 is the negative input terminal of the step-down circuit. The primary positive electrode of the transformer L2 is connected in series with resistors R4 and R5 and then electrically connected to the power supply terminal of the step-down chip U1. The primary negative electrode of the transformer L2 is electrically connected to the output current terminal of the step-down chip U1.

[0054] The power supply terminal of the buck chip U1 is grounded through the electrolytic capacitor EC3 and the capacitor C5 respectively, and the current feedback terminal cs of the buck chip U1 is grounded through the resistor RS1 and the resistor RS2 respectively.

[0055] In this embodiment, the buck chip U1 is an OB2734 buck chip.

[0056] The step-down circuit is electrically connected to the USB output circuit via a synchronous rectification circuit; the synchronous rectification circuit includes a synchronous rectification chip U2, a resistor R13, a capacitor C7, and a capacitor C8;

[0057] The transistor output pins of the synchronous rectifier chip U2 are all electrically connected to the negative output terminal of the step-down circuit. The negative output terminal of the step-down circuit is connected in series with resistor R13 and capacitor C7, which are electrically connected to the negative input terminal of the USB output circuit. The ground terminal of the synchronous rectifier chip U2 is electrically connected to the negative input terminal of the USB output circuit. The power supply terminal of the synchronous rectifier chip U2 is grounded through capacitor C8.

[0058] In this embodiment, the synchronous rectification chip U2 is an OB2013 synchronous rectification chip.

[0059] The emergence of new, high-efficiency rectification technologies, such as synchronous rectification, offers a potential solution to these problems. By employing low-on-resistance power devices and advanced control strategies, energy losses during rectification can be significantly reduced, output efficiency and stability can be improved, and the demands of modern electronic devices for fast and safe charging can be better met.

[0060] This embodiment has the following effects:

[0061] 1. Stable power supply: Highly efficient rectifier output ensures that connected USB devices receive stable, continuous, and non-fluctuating power, eliminating the risk of device damage or malfunction due to voltage instability.

[0062] 2. Fast charging capability: It can provide a larger current output, significantly shortening the charging time of electronic devices such as mobile phones and tablets, and improving user efficiency.

[0063] 3. Strong compatibility: It can adapt to a variety of USB devices of different types and specifications, whether it is low-power headphones, smart watches, or high-power demanding laptops, etc., it can achieve good compatibility and charging effects.

[0064] 4. Energy saving and high efficiency: Efficient rectification technology reduces the loss of energy during the conversion process, which not only reduces the energy consumption of the power strip itself, but also helps to save energy, which is in line with the modern concept of energy saving and environmental protection.

[0065] 5. Protect device battery life: Stable and accurate power output helps optimize the charging process, reducing adverse conditions such as overcharging and undercharging, thereby extending the service life of the battery of the connected device.

[0066] 6. Improve electricity safety: By optimizing the rectifier output, the risk of circuit failure is reduced, and potential safety hazards such as short circuit and overload are reduced, providing users with a more reliable electricity environment.

[0067] 7. Compact and multifunctional design: Achieve efficient rectification output without increasing excessive volume, provide users with more socket interfaces, and meet the needs of charging and using multiple devices at the same time.

[0068] 8. Reduce electromagnetic interference: Good rectification design can effectively reduce electromagnetic radiation and interference, avoiding affecting the normal operation of other electronic equipment.

[0069] In the description of the present application, the description with reference to the terms "one embodiment", "some embodiments", "in the present embodiment", "specific example", or "some examples" means that the specific features, mechanisms, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, mechanisms, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0070] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A USB power strip with high-efficiency rectifier output, characterized in that: Including AC circuit, bridge rectifier circuit, filter circuit, step-down circuit and USB output circuit; The input end of the AC circuit is electrically connected to the live wire and the neutral wire. The output end of the AC circuit is electrically connected to the USB output circuit after being connected in series with a bridge rectifier circuit, a filter circuit, and a step-down circuit. The USB output circuit includes a current limiting protection chip U4, a Type-C interface, and a Type-A interface. The Type-C interface and the Type-A interface are both electrically connected to the current limiting protection chip U4. The ground ends of the Type-C interface and the Type-A interface are both grounded through a current detection resistor, and both ends of the two current detection resistors are electrically connected to the current limiting protection chip U4.

2. The USB power strip with high-efficiency rectifier output according to claim 1, characterized in that: Also included is a PD fast charge feedback circuit, the PD fast charge feedback circuit including a photocoupler U3; The positive output end of the step-down circuit is electrically connected in series with a capacitor C6 and the positive electrode of the photoelectric coupler U3. A resistor R12 is connected in parallel at both ends of the capacitor C6. The negative electrode of the photoelectric coupler U3 is electrically connected to the current limiting protection chip U4. The positive electrode of the photoelectric coupler U3 is electrically connected to the negative electrode of the photoelectric coupler U3 through the resistor R1. The emitter of the photoelectric coupler U3 is grounded, and the collector of the photoelectric coupler U3 is electrically connected to the voltage feedback end of the step-down circuit. The collector of the photoelectric coupler U3 is grounded through the series resistor R10 and the capacitor C4.

3. The USB power strip with high-efficiency rectifier output according to claim 1, characterized in that: The AC circuit includes a power plug, a fuse F1, a thermistor RT1, and an electromagnetic interference filter; The power plug is provided with a live wire connection end for electrically connecting to the live wire and a neutral wire connection end for electrically connecting to the neutral wire, the live wire connection end being electrically connected to the first AC input end of the bridge rectifier circuit via a series fuse F1, and the neutral wire connection end being electrically connected to the second AC input end of the bridge rectifier circuit via a thermistor RT1; The electromagnetic interference filter includes a capacitor CX1, a resistor RX1, a resistor RX2, a resistor RX3, and a resistor RX4; the capacitor CX1 is electrically connected between the first AC input terminal of the bridge rectifier circuit and the second AC input terminal of the bridge rectifier circuit, the resistor RX1 and the resistor RX2 are connected in series and then connected in parallel to both ends of the capacitor CX1, and the resistor RX3 and the resistor RX4 are connected in series and then connected in parallel to both ends of the capacitor CX1.

4. The USB power strip with high-efficiency rectifier output according to claim 1, characterized in that: The filter circuit includes an inductor L1, an inductor RL2, an electrolytic capacitor EC1, an electrolytic capacitor EC2, a capacitor C1, a capacitor C2, a diode D1, a resistor R1, a resistor R6 and a resistor R7; The DC positive electrode of the bridge rectifier circuit is electrically connected to the positive input terminal of the step-down circuit through the inductor L1, the DC negative electrode of the bridge rectifier circuit is grounded through the inductor RL2, the electrolytic capacitor EC1 is electrically connected between the DC positive electrode of the bridge rectifier circuit and the DC negative electrode of the bridge rectifier circuit, and the electrolytic capacitor EC2 is electrically connected between the positive input terminal and the negative electrode of the step-down circuit; The positive input terminal of the step-down circuit is electrically connected to the negative input terminal of the step-down circuit after being connected in series with capacitor C1, capacitor C2 and resistor R6. The resistor R1 is connected in parallel across the capacitor C1, and the resistor R7 is connected in parallel across the resistor R6. The connection end of the capacitor C1 and capacitor C2 is electrically connected to the negative electrode of the diode D1, and the connection end of the capacitor C2 and resistor R6 is electrically connected to the positive electrode of the diode D1.

5. The USB power strip with high-efficiency rectifier output according to claim 1, characterized in that: The step-down circuit includes a transformer L2 and a step-down chip U1; The primary positive electrode of the transformer L2 is the positive input terminal of the step-down circuit, and the primary negative electrode of the transformer L2 is the negative input terminal of the step-down circuit. The primary positive electrode of the transformer L2 is connected in series with the resistor R4 and the resistor R5, and then electrically connected to the power supply terminal of the step-down chip U1. The primary negative electrode of the transformer L2 is electrically connected to the output current terminal of the step-down chip U1. The power supply terminal of the buck chip U1 is grounded through the electrolytic capacitor EC3 and the capacitor C5 respectively, and the current feedback terminal cs of the buck chip U1 is grounded through the resistor RS1 and the resistor RS2 respectively.

6. The USB power strip with high-efficiency rectifier output according to claim 5, characterized in that: The step-down chip U1 is an OB2734 step-down chip.

7. The USB power strip with high-efficiency rectifier output according to claim 1, characterized in that: The step-down circuit is electrically connected to the USB output circuit via a synchronous rectification circuit; the synchronous rectification circuit includes a synchronous rectification chip U2, a resistor R13, a capacitor C7 and a capacitor C8; The transistor output pins of the synchronous rectifier chip U2 are all electrically connected to the negative output terminal of the step-down circuit, the negative output terminal of the step-down circuit is connected in series with the resistor R13 and the capacitor C7 and is electrically connected to the negative input terminal of the USB output circuit, the ground terminal of the synchronous rectifier chip U2 is electrically connected to the negative input terminal of the USB output circuit, and the power supply terminal of the synchronous rectifier chip U2 is grounded through the capacitor C8.

8. The USB power strip with high-efficiency rectifier output according to claim 7, characterized in that: The synchronous rectification chip U2 is an OB2013 synchronous rectification chip.

9. The USB power strip with high-efficiency rectifier output according to claim 1, characterized in that: The current limiting protection chip U4 is a HUSB382 current limiting protection chip.

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